Term DefinitionOxidation Loss of Electrons and Hydrogen, Gain of oxygen Reduction Gain of Electron and Hydrogen, Loss of oxygen Cell Respiration The controlled release of energy, in the form of ATP, from organic compounds Chemiosmosis H+ ions moving down a concentration gradient into the mitochondrial matrix Products of glycolysis - ATP - NADH/H+ - Pyruvate Outline the process of glycolysis - Takes place in cytoplasm - Substrate is glucose - Phosphorylation of glucose - To form hexose bisphosphate - Requires ATP - Two triose phosphate converted into two pyruvate - Oxidation by removal of hydrogen - To produce two NADH + H+ - Net gain of two ATP per glucose Describe the role of acetyl CoA in aerobic respiration - Two carbon acetyl fragments - Intermediate product between glycolysis and Kerbs cycle - Intermediate product between fat metabolism and Kerbs cycle - Acetyl group binds with coenzyme A - Passes acetyl group to Krebs cycle Describe the role of acetyl CoA in carbohydrate and fat metabolism - Acetyl CoA enters Kerbs cycle - Glucose converted to pyruvate in glycolysis - Glycerol undergoes glycolysis and is converted to pyruvate - Pyruvate enters mitochondria - Pyruvate converted to acetyl CoA - By oxidative decarboxylation - Fat enters mitochondria - Fats oxidised to acetyl CoA - “regulates” rate of fat metabolism Explain the link reaction that occurs between glycolysis and Kerbs cycle - Pyruvate enters a mitochondrion - Enzymes in the matrix of mitochondria remove one carbon dioxide and hydrogen from the pyruvate - Hydrogen is accepted by NAD - Removal of hydrogen is oxidation - Removal of Carbon Dioxide is Decarboxylation - The product is an acetyl group which reacts with CoA - acetyl CoA enters Kerbs cycle Describe how the link reaction and the Krebs cycle are related - Both occur in the matrix of the mitochondria - acetyl CoA produced in the link reaction enters the Krebs cycle - acetyl group joins with 4 carbon compound/OAA from cycle Explain the processes involved in the Krebs cycle - Krebs cycle only occurs in aerobic conditions - Krebs cycle occurs in the mitochondria - acetyl CoA from the link reaction releases an acetyl group - NADH+H+ and CO2 are formed with each decarboxylation - Removal of CO2 involves oxidative decarboxylation - and the release of energy - acetyl group is joined to a 4 carbon molecule/OAA to form a 6 carbon molecule - Decarboxylation changes citrate to 5 carbon molecule - Decarboxylation changes glutamate to a 4 carbon molecule - Then converted into the original OAA and the cycle repeats - One molecule of ATP is made during this step - 3 NADH,1 FADH2 and CO2 are end products of Krebs cycle Describe the function of oxygen in oxidation phosphorylation - Oxygen is the final acceptor of protons - Water is formed - In the electron transport chain - Increases yield of ATP Explain how chemiosmosis assists in ATP production during oxidative phosphorylation - Occurs during aerobic respiration - Oxidative phosphorylation occurs during the electron transport chain - Hydrogen and electrons are passed between carriers - Releasing energy - Finally joining with oxygen to produce water - Occurs in cristae of mitochondria - Chemiosmosis is the movement of hydrogen ions - Protons are moved against their concentration gradient - Into the space between the two membranes - Protons flow back to the matrix - Through the ATP synthase - Energy is released which produces more ATP Describe the processes that occur in the mitochondria of cells when oxygen is present - Glucose converted to pyruvate - Pyruvate decarboxylated and NADH + H+ is formed - acetyl group reacts with coenzyme A to form acetyl CoA - acetyl CoA enter Krebs cycle - 2 CO2 molecules removed - NADH + H+ formed - For each pyruvate, 3 NADH + H+ and 1 FADH2 formed - 1 ATP formed per pyruvate each turn - NADH + H+ and FADH2 enter electron transport chain - Oxidative phosphorylation uses energy released by ETC to synthesise ATP - H+ move into inter membrane space - Creates H+ gradient across the membrane - ATP synthesised by flow of H+ back across membrane through ATP synthase - ATP synthesised by chemoosmosis - ETC reduces oxygen Explain why the Krebs cycle cannot continue if electron transport stops in a mitochondrion - Supply of NAD would run out - NAD needed to accept Hydrogen in Krebs cycle - NADH + H+ is reduced in oxidative phosphorylation - Supply of ADP runs out Explain how energy is released and used to make ATP by electron carriers in the electron transport chain during aerobic respiration - Electron carriers found on cristae of mitochondria - H+ transported to electron carriers by NAD and FAD - Electrons are passed along electron transport system - Carrier is oxidised as it loses an electron to the next carrier, which becomes reduced - Energy released during electron transport causes proton pumping - Electrons are passed down energy gradient - Establishes proton gradient in inter membrane space - Oxygen is the final electron acceptor - Generation of ATP through chemiosmosis Explain the role of cristae in mitochondria - Increase the surface area of inner mitochondrial membrane - Allow electron transport because of embedded proton electron carriers - Facilitate proton pumping because of high surface to volume ratio - Increase ATP production because of ATP synthase embedded in membrane Explain how the structure of the mitochondrion allow it to carry out its functions efficiently - Membranes to separate from processes in the cytoplasm - Small size gives larger surface area to volume ratio - Large surface area to volume ratio allows rapid exchange of materials - Matrix contains enzymes of the Krebs cycle - Matrix is an aqueous solution so allowing enzymes to work - Inner membrane forms cristae to increase the surface area - Large surface area gives more space for electron transport chain/oxidative phosphorylation - Inner membrane contains ATP synthase - Narrow gap between inner and outer membrane - Proton concentration gradient rapidly established - Chemiosmosis therefore more efficient - DNA present to act as genetic material - Ribosomes for protein synthesis - Some proteins do not need to be imported Explain how chemical energy for use in the cell is generated by electron transport and chemiosmosis - NAD/FAD is reduced by gaining two H atoms - Reduced NAD produced in glycolysis, link reaction, Kerbs cycle - Reduced NAD/FAD delivers hydrogen atoms to ETC - ETC is in mitochondrial cristae - Electrons release energy as they flow along the chain/from carrier to carrier - Electrons from ETC accepted by oxygen - Proteins in the inner mitochondrial membrane acts as proton pumps - Protons pumped into inter membrane space/proton concentration higher in inter membrane space than in matrix - Energy from electrons used to pump protons into intermembrane space - ATP synthase in mitochondrial cristae - Energy released as protons pass down through ATP synthase - ATP synthase converts ADP to ATP - Oxidative phosphorylation is ATP production using energy from oxidising foods Explain anaerobic and aerobic respiration - Pyruvate fully oxidised - By the link reaction and Krebs cycle - Reduced NAD passes electrons to electron transport chain - H+ gradient generated - Oxygen required as terminal proton acceptor - Proton gradient used by ATP synthase to produce ATP - Glucose transformed into two molecules of pyruvate - Producing reduced NAD - Smaller amount of energy released than in aerobic - NAD regenerated by reducing pyruvate - Pyruvate to CO2 and ethanol in yeast - Pyruvate to lactic acid in humans Distinguish between anaerobic and aerobic respiration Aerobic Anaerobic Requires Oxygen Does not require Oxygen In cytoplasm and mitochondria In cytoplasm Oxygen reduced Pyruvate reduced High yield of ATP Low yield of ATP High yield of NADH + H+/FADH2 produced Lower yield of NADH + H+ End products: CO2 and H2O End products are ethanol and CO2/lactate Can use fats Only sugars Involves oxidative phosphorylation/ETC Does not Involves oxidative phosphorylation/ETC Involves Kerbs cycle Does not involve Kerbs cycle Compare the structure of a chloroplast and a mitochondrion - Both are double membrane organelles - Both contain DNA - Both contain ribosome - Both have electron transport chain - Both produce ATP by chemiosmosis - Both contain ATP synthase - Site of photosynthesis - Thylakoid membranes - Chlorophyll to absorb light - Light generated ATP production - H+ gradient across thylakoid membrane - Site of respiration - ATP production by oxidation of organic molecules - H+ gradient across inner membrane Outline the cellular location of different named processes in photosynthesis and cell respiration - Chlorophyll for light absorption - Thylakoid for chemoosmosis - Stroma for Calvin cycle - Thylakoid space for build up proton concentration gradient - Inner membrane of thylakoid for electron transfer - Inner membrane for ATP synthesis - Mitochondria for ATP production - Cytoplasm for glycolysis - Matrix for Link reaction and Kerbs cycle - Double membrane of mitochondria for chemiosmosis - Inter-membrane space for build up H+ concentration gradient - Inner membrane of mitochondria for electron transfer - Inner membrane for ATP synthesis